The present invention relates to electronic alarm systems. More particularly, the present invention relates to an adaptable interface unit for use with an existing alarm system, e.g., an existing electronic automobile alarm system, that adds a wide variety of programmable features to the alarm system that would not otherwise be available.
Alarm systems are known in the art. A typical alarm system is installed for the purpose of securing a defined area from unauthorized intrusion or trespass. The defined area that is secured by the alarm system will usually comprise a closed area, such as specified room(s) within a building, or an entire building or house. In the case of automobile alarm systems, the secured area typically comprises the interior of an automobile, or other motorized or non-motorized vehicle, and may also extend to unauthorized tampering with the exterior of the automobile.
All alarm systems have certain basic elements in common. Conventional electronic automobile alarm systems, for example, typically include at least the following basic components: (a) a plurality of sensors or detectors; (b) an alarming device or mechanism, e.g., an audible alarm siren or horn; (c) an arming circuit; and (d) a control unit.
The plurality of sensors or detectors are used to sense an entry event or other activity that could be viewed as an unauthorized tampering or presence (hereafter a "violation condition" or "violation event"). Each of the plurality of sensors is fashioned to be responsive to a particular type of violation condition, such as movement of the automobile, prolonged close proximity of a person to the automobile, excessive acoustic energy within the automobile (as occurs with glass breakage), or the opening of a door or portal into one of a plurality of compartments within the automobile. Further, each sensor generates a violation signal in response to the violation condition.
The plurality of sensors are coupled, usually with electrical wires (although RF or other communication links may also be used), to the control unit. Thus, any generated violation signal is coupled to the control unit, and in response thereto, the control unit activates the alarming output device. The alarming device usually comprises an audible alarm, siren, horn or bell, and when activated is intended to scare off the would-be intruder and to draw attention to the fact that an intrusion or other violation condition has been detected.
Some alarm systems, in response to a violation signal, transmit an alarm signal to a remote location, such as a police station or a neighboring facility. The alarm signal, when received at the remote location, indicates a violation condition has been detected. The control unit continues to activate the alarm device until the control unit is reset or until the control unit is disarmed. Typically, the control unit will reset automatically after a prescribed period of time from first sensing the violation condition.
A simple automobile alarm system may use the automobile's existing electrical system (used, for example, to turn on a light when a door is opened) as the plurality of sensors that are connected to a suitable control unit. A violation condition may thus be sensed if the door is opened when the control unit is armed and if too much time passes (typically 10 to 15 seconds) before the control unit is disarmed (turned off).
More sophisticated automobile alarm systems supplement the above-described basic alarm system with additional sensors (e.g., that sense the opening of the hood or trunk, the removal of an automobile cover, or the presence of "motion" within the automobile) and a correspondingly more complex control unit. Such sophisticated systems may also include backup battery protection and remote paging capabilities so that when a violation signal is generated, a paging device carried by the automobile operator will sound or otherwise indicate that the violation condition has occurred. Further, it is not uncommon for such systems to take more preventative steps than merely sounding an alarm. For example, automobile alarm systems are known in the art that, upon sensing a violation condition (such as the opening of the door, trunk or hood while the system is armed), will disable the ignition and/or fuel delivery system of the automobile's engine, thereby rendering it impossible to drive the automobile under its own power.
A feature common to all automobile alarm systems is the ability to selectively arm or disarm the system. The arming circuit of a simple alarm system generates an "ARM" signal after a prescribed time delay, such as 15 seconds, following the manual setting of an arming switch inside of the automobile. (Typically, such switch is "hidden" or otherwise made non-conspicuous so that only the automobile's owner knows of its location and function.) This type of simple alarm system arming is known in the art as passive arming. The prescribed time delay subsequent to the arming of the system allows the automobile owner sufficient time to exit the automobile prior to the system becoming armed. Similarly, upon reentering the automobile, as mentioned above, another time delay allows the owner sufficient time to manually disarm the system before a violation condition is sensed. The arming circuit of a basic alarm system will generate a "DISARM" signal following the manual setting of the arming switch inside the automobile.
Alternatively, the arming circuit of an alarm system may include an arming receiver and an arming transmitter. The arming transmitter provides an "ARM" transmission and a "DISARM" transmission when activated by the automobile operator. Typically, the "ARM" transmission and the "DISARM" transmission are substantially identical radio frequency (RF) pulses generated by the arming transmitter, however in a more advanced alarm system different RF pulses may be used for the "ARM" transmission and the "DISARM" transmission. The "ARM" transmission and the "DISARM" transmission are received by the arming receiver, coupled to or included within the control unit, when the arming transmitter is proximate to the arming receiver. In response to the "ARM" and "DISARM" transmissions, the arming receiver generates the "ARM" and "DISARM" signals respectively. Note that when substantially identical RF pulses are used for the "ARM" and "DISARM" transmissions, the arming receiver generates the "ARM" and "DISARM" signals after successive RF pulses, respectively, i.e., the arming receiver toggles between ARM and DISARM states. In a more advanced alarm system, using different RF pulses for the "ARM" and "DISARM" transmissions, the arming receiver generates the "ARM" signal or the "DISARM" signal in response to the particular "ARM" or "DISARM" RF pulse that is received.
The "ARM" and "DISARM" signals are used to arm and disarm the control unit respectively. Once armed, each of the plurality of sensors is enabled and sensitive to a violation condition. When a sensor detects the violation condition and the control unit is armed, the alarm device is activated. Additionally, an indicator, such as a light emitting diode (LED), is typically turned on when the system is armed. The LED indicates to the automobile operator that the system is armed, and also serves to let a would-be intruder know that the automobile is protected by an armed automobile alarm system. When the control unit is disarmed, the plurality of sensors are disabled, the alarm device cannot be activated, and the LED indicator is turned off.
A major concern with conventional automobile alarm systems relates to their cost and complexity of installation. To illustrate, a simple automobile alarm system (e.g., one that uses only the existing wiring of the automobile) can be inexpensively manufactured and simple to install (and therefore quite affordable to the owner). Unfortunately, the simple alarm system does not have many features desired by most automobile owners. Heretofore, when owner of an automobile wanted to upgrade his or her existing automobile alarm features, it was necessary to replace their existing automobile alarm system with a more advanced alarm system that provides the desired features. Problematically, such replacement can only be achieved by removing the existing alarm system, thereby incurring removal expense, and installing the new alarm system, thereby incurring installation expense. Disadvantageously, the expense of removal and replacement discourages many owners from having an automobile alarm system that includes all the features they may need or desire. Thus, what is needed is an inexpensive means of adapting an existing automobile alarm system to include additional features not available with the existing alarm system.
The present invention advantageously addresses the above and other needs.